Freight container

ABSTRACT

A freight container ( 1 ) having a base ( 2 ) and a roof ( 5 ) wherein fittings ( 8, 9 ) for lifting the container and/or stacking a second container on the roof are provided with a support strut ( 24 ) moveably mounted on the container such that the support strut can be moved from a load-bearing position in which the support strut transfers a load between the fittings and the base during lifting and stacking and a loading position in which the support strut does not substantially impede loading and unloading of the freight container from a side of the container. The support strut is carried on one side of a gate structure ( 20 ) hinged to a corner post ( 3, 4 ) of the container by a hinge at the opposite side.

FIELD OF THE INVENTION

Intermodal freight transport in Europe (by road, rail and sea ferry)requires containers of maximum internal volume and minimum tare weight.Current European regulations allow a maximum container length of 13.6 mand a maximum width of 2.5 m/2.55 m. This width can accommodate two rowsof 1.2 m standard pallets which, after allowing for practicalclearances, allows 40 mm or so at most for each of two side wallstructures.

Swapbody containers of 13.6 m currently exist, these containers havecorrugated steel sides which are specially strengthened at locations12.2 m (40 feet) apart along the sides (ie at the “40 feet” location) toprovide, in effect, 12.2 m (40 feet) posts. At the top of each 12.2 m(40 feet) post is a standard I.S.O. fitting (corner casting) whichallows the container to be top-lifted by a known 12.2 m (40 feet)spreader with twistlock connectors. Also, a standard laden 1 2.2 m (40feet) container may be stacked on top of such a container.

However, such containers suffer from a drawback that freight cannot beloaded or unloaded except through a rear end door, whereas the greatmajority of road trailers (of this size) are curtain sided, which hasthe great advantage of allowing side loading and unloading.

The roof structure of 13.6 m curtainside swapbody containers now incommon use is relatively flimsy. This is necessitated by therequirements for maximum side aperture height, which limits thestructural depth allowable for the roof (commonly no more than 100 mmapproximately). For the same reason, the structural depth of the basehas to be kept to a minimum (currently approximately 250 mm) whichresults in a very flexible base structure which deflects verysignificantly when under load.

It is therefore impractical to stack a laden 12.2 m (40 feet) unit ontop of a 13.6 m curtainside container, nor can a laden 13.6 mcurtainside unit be stacked on top of another container, since excessivebase deflection would cause unacceptable loadings on the roof of thecontainer underneath. Notionally, a rigid-walled 13.6 m unit could bestacked on a curtainside one, except that significant longitudinalracking forces would arise during transport and it is unlikely that thecurtainside container could safely resist these longitudinal forces.

However, there is a strong demand, currently unsatisfied, for 13.6 mcurtainside containers which also have the capability of being stackedladen and top-lifted. Top lifting equipment is readily available at mostdocksides and intermodal depots; whereas, grapple lifting or slinglifting equipment is not readily available, being very specialised. Shipto shore container cranes invariably have top lifting equipment and aLift On Lift Off (LO-LO) operation is highly desirable for deck cargoeson short-sea ferries. Also, many ferries carry containers stackedtwo-high below decks on Maffi-type platforms/cassettes. These Mafficassettes commonly have a capacity of 70,000 kg (70 tonnes) and arerolled on and off the ship (RO-RO) with special tractors. Currently,only a single curtainside container can be transported by this system,resulting in the waste of valuable ship space. In effect, an operatorhas to pay for two container slots, when moving only one container.

13.6 m curtainside containers currently have I.S.O. fittings (or similarlightweight versions) in their base structure at the 12.2 m (“40 feet”)locations. The purpose of these fittings is to allow twistlockconnection of the container to a road chassis (trailer), a rail wagon orto a ship's deck. If a full I.S.O. fitting were provided in the roofstructure at each 12.2 m (“40 feet”) location, and the top and bottom12.2 m (“40 feet”) fittings connected by a structural “post” member,then the container would be top liftable and stackable. Unfortunately,such “posts” would prevent satisfactory side loading and unloading ofthe container.

One manner for overcoming the difficulty would be to make the 40 feetposts removable, however, this presents a further difficulty in that thepost is necessarily heavy and impractical to be removed safely bymanpower. Also, it would not be easy to make a satisfactory connectionto the container at the top of the post, since the top is a long wayfrom the ground and therefore, not easily accessible.

SUMMARY OF THE INVENTION

It is an object of the present invention to at least mitigate theforegoing difficulties.

According to the present invention there is provided a freight containerincluding a base, a roof, fitting means located on the roof for liftingthe container and/or stacking a second container on the roof, andsupport means moveably mounted on the container, the support means beingmoveable between a load-bearing position for transferring a load betweenthe fitting means and the base and a loading position in which thesupport means does not substantially impede loading and unloading of thefreight container from a side of the container, wherein the supportmeans is located on gate means (20) hingedly fixed to corner posts (3,4) in corners of the container.

Conveniently, the support means is a substantially vertical strut.

Advantageously, locking means are provided for locking the support meansin the support position.

Conveniently, two fitting means are mounted on the roof proximate ajunction of the roof with a side wall of the container, the two fittingsbeing separated by a predetermined distance less than a length of theside wall.

Preferably, the predetermined distance is 12.2 metres (40 feet).

Conveniently, a transverse roof beam is provided to connect fittingmeans located proximate opposed side walls.

In one embodiment, the present invention overcomes the above noteddifficulties by mounting the removable 12.2 m (40 feet) posts on ahinged “gate” structure such that the whole structure can be swung outof the way, yet remain easily in control of the operator. Connections atthe top and bottom of the 12.2 m (40 feet) post comprise a spigot and asocket system which automatically engages when the gate is swung “shut”.To assist engagement/disengagement the spigots and sockets are tapered.

In order to force the connections into engagement and to hold themsecurely engaged (also to force them out of engagement) standard doorlocking gear is used. This comprises a tubular shaft running from thetop to the bottom of each “gate”. At the ends of the shaft are speciallyshaped claw-type cams which engage with matching cam-keepers fixed tothe main structure. As the shaft is rotated (using a handle or levernear the bottom of the shaft, where it is easily accessible) the “gate”is forced shut and the spigot connections forced into engagement. Thehandle is then secured in the “shut” position and the top and bottomconnections of the 12.2 m (40 feet) post are thereby secured. The firstcontainer may now be safely top lifted, also a second laden unit may bestacked on top of the first container.

The achievement of top lift and laden stacking capabilities does involvesignificant additional tare weight compared with similar containerswhich do not have these capabilities. The reasons for the extra weightare, of course, the weight of the 12.2 m (40 feet) posts themselves andthe associated gate structure, also the weight of a substantialtransverse roof beam which is needed to resist the eccentricity momentsarising at the I.S.O. top lift fittings. The eccentricity occurs becausethe 12.2 m (40 feet) post (of necessity) is located close to the 2.5 mouter “envelope” (so as to allow internal width for two 1.2 m palletsside by side) whereas the twistlocks come well inside the ISO 2.438 m“envelope”. In addition, the complete structure, in particular the basestructure, has to be heavier in order to comply with the internationalContainer Safety Convention (CSC) which is legally obligatory for topliftable containers. In order to obtain CSC Certification the unit hasto be tested to 2.0 R (where R equals the maximum gross rated mass)whereas the grapple and sling lifted units do not require CSCCertification, they merely have to comply when CEN standards forswapbodies which call for testing to 1.5 R only.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described by way of example with reference tothe accompanying drawings, in which:

FIG. 1 shows a side view of a freight container according to theinvention with the gate in a load-bearing position;

FIG. 2 shows a partial view of the freight container of FIG. 1 mountedon a lorry with the gate in a freight loading/unloading position;

FIG. 3 shows a plan view of the partial view of the container shown inFIG. 2;

FIG. 4 shows a view of a locking mechanism used in a preferredembodiment of the invention;

FIG. 5 shows a cross-section along double arrow headed line V—V in FIG.4;

FIG. 6 shows a cross-section along double arrow headed line VI—VI inFIG. 4;

FIG. 7 shows a container of the invention being lifted;

FIG. 8 shows a container shorter than the container of the invention,stacked on a roof of a container of the invention;

FIG. 9 shows a container of the same length of the container of theinvention, loaded on a container of the invention;

FIG. 10 shows two containers of the invention stacked one above theother on a cassette for loading on a roll on/roll off ferry; and

FIG. 11 shows a container shorter than the container of the inventionstacked on a container of the invention, loaded on a cassette forloading on a roll on/roll off ferry; and

FIG. 12 shows details of the gate of FIG. 1.

DETAILED DESCRIPTION

In the figures, like reference numerals denote like parts.

As shown in FIGS. 1-3 a freight container 1 of the invention has a base2 and corner posts 3, 4 supporting a roof 5, the roof being additionallysupported by three equally spaced intermediate posts 6 which are movablein a known manner. The sides of the container are closed by a curtain 7covering the intermediate posts 6, such that the curtain 7 may be drawnaside for loading and unloading the container 1. The container isprovided adjacent to its sides on its base and roof with known I.S.Ocorner fittings 8, 9, 10, 11 which are separated by a distance of 12.2 m(40 feet) along the side of the container such that the roof cornerfittings 8, 9 are vertically above the base corner fittings 10, 11respectively.

There is further provided a gate structure 20 hinged to each of thecorner posts 3, 4 including a hinged vertical member 21, top 22 andbottom 23 horizontal members and a load bearing vertical member 24,which is so arranged that in the closed or load-bearing position, theload bearing member 24 is aligned with a roof corner fitting 8, 9 and abase corner fitting 10, 11 respectively to transfer load between them.The structure is further provided with a diagonal member 25 to stabilizethe gate structure 20 which diagonal member 25 is fixed between ajunction between the lower horizontal member 23 and the hinged verticalmember 21 and a junction between the upper horizontal member 22 and theload bearing member 24. As best shown in FIG. 3, the gate structure 20is hinged so that the gate can rotate through 135° about a vertical axisthrough the hinges from the closed load bearing position to an openloading/unloading position, as indicated by the double-headed arrow A sothat the gate structure 20 does not impede side loading and unloading ofthe container 1.

As also shown in FIG. 3, the roof 5 is strengthened by a substantialtransverse roof beam 12 which is needed to resist eccentricity momentsarising at the I.S.O. top lift fittings. This eccentricity occursbecause the 12.2 m (40 feet) post is (of necessity) located close to the2.5 m outer “envelope” (so as to allow internal width for two 1.2 mpallets side by side), whereas the twistlocks come well inside theI.S.O. 2.438 m “envelope”.

To load or unload the container 1, the curtain 7 is drawn aside and theintermediate moveable posts 6 removed in a known manner and the gatestructure 20 is moved from the load-bearing position to the openloading/unloading position. When the loading or unloading is completed,the gate structure 20 is moved to the load-bearing position and lockedin position in a manner to be described. The moveable posts 6 arereplaced and the curtain 7 closed.

As shown in FIGS. 4 to 6, and FIG. 12, the gate 20 is locked in theload-bearing position by a known door locking mechanism 30 in whichstandard door locking gear is used to force the connections intoengagement and to hold them securely engaged. (The door locking gear isalso used to force the connections out of engagement to open the gate.)The locking gear comprises a tubular shaft 31 running from top to bottomof each “gate” 20. At the ends of the shaft are specially shapedclaw-type cams 32 which engage with matching cam-keepers 33 fixed to themain structure. As the shaft 31 is rotated using a handle or lever 34(FIG. 12) near the bottom of the shaft 31, where it is easilyaccessible, the “gate” 20 is forced shut and spigot connections 35forced into engagement. The handle 34 is then secured in the “shut”position and the top and bottom connections of the 12.2 m (40 feet) post24 are thereby secured. A first container 1 may now be safely toplifted, also a second laden container may be stacked on top of the firstcontainer.

FIGS. 7-11 show the container 1 of the invention in use with the gate 20in the closed or load-bearing support position. As shown in FIG. 7, thecontainer 1 can be lifted in the direction of arrows B when fully laden,using known top lifting equipment and twistlock connections to the rooffittings 8, 9. FIG. 8 illustrates a laden I.S.O. 12.2 m (40 feet)container 40 stacked on a curtain-sided container 1 of the presentinvention on a ship's deck 41, ie, for a lift on/lift off system. Asimilar application is shown in FIG. 9, where a 13.6 m swapbody 50 withrigid walls is stacked on top of a container 1 of the present invention.

As shown in FIG. 10, two laden containers 1 of the present invention maybe stacked on a 70 tonne “Maffi”-type cassette 60 for loading onto aroll on/roll off ferry. Spacers 61 are provided between the stackedcontainers to allow flexing of the base of the upper container.Similarly, as illustrated in FIG. 11, an I.S.O. 12.2 m (40 feet)container 70 may be stacked on a container 1 of the present invention,the load being transmitted to the base through the load-bearing member24.

FIG. 12 shows details of the gate 20.

What is claimed is:
 1. A freight container (1) including a base (2),corner posts (3, 4) located on the base in corners of the container tosupport a roof (5), fitting means (8, 9) located on the roof for liftingthe container and/or stacking a second container on the roof, and asubstantially vertical struts (24) moveably mounted on the container,the substantially vertical struts being moveable between load-bearingpositions for transferring a load between the fitting means and the baseand loading positions in which the substantially vertical struts do notsubstantially impede loading and unloading of the freight container,gate means (20) swingable between an open position for loading andunloading the container and a closed position for the containers saidgate means having first and second opposite sides, said gate means (20)being hingedly fixed to respective said corner posts (3, 4) by hingemeans on the first side of the gate means and the substantially verticalstruts each being located on the gate means at the second opposite sideof the gate means remote from the hinge means.
 2. A freight container asclaimed in claim 1, wherein locking means (30) are provided for lockingthe substantially vertical strut in the support position.
 3. A freightcontainer as claimed in any of the preceding claims, wherein two of thefitting means (8, 9) are mounted on the roof proximate a junction of theroof with a side wall of the container, the two fitting means beingseparated by a predetermined distance less than a length of the sidewall.
 4. A freight container as claimed in claim 3, wherein thepredetermined distance is 12.2 meters (40 feet).
 5. A freight containeras claimed in claim 1, wherein each said vertical strut is secured atsaid second opposite side of the gate means for being swung outwardlyand away from the container as said gate means is swung to said openposition.
 6. A freight container as claimed in claim 5, wherein eachsaid strut is outside the container in said open position of the gatemeans.
 7. A freight container as claimed in claim 5, wherein each saidstrut extends along said second side of said gate means oversubstantially the entire length of said second side.
 8. A freightcontainer as claimed in claim 5, wherein each said strut extendscontinuously along said second side of the gate means.
 9. A freightcontainer as claimed in claim 1, wherein said container has side wallsand end walls, said gate means being disposed at one of said side wallsof the container.
 10. A freight container as claimed in claim 9, whereinsaid fitting means comprises two fitting members spaced apart on theroof at said one of the side walls of the container.
 11. A freightcontainer as claimed in claim 1, wherein with said gate means in saidloading position and the vertical struts do not impede loading andunloading of the container, there is clear open space between the roofand the base at said fitting means.
 12. A freight container as claimedin claim 1, wherein said gate means comprises a swingable gate memberswhich open and close an opening in the container, each said gate memberhaving one side edge hingeably connected to a respective said cornerpost and an opposite side edge at which a respective said substantiallyvertical strut is secured, said locking means comprising locking memberson said vertical struts at upper and lower ends thereof for respectiveconnection to said fitting means and said base for locking said gatemembers in the closed position and engaging said vertical struts in saidload-bearing positions.
 13. A freight container as claimed in claim 12,wherein in said closed position of the gate members, said verticalstruts are disposed at an intermediate location between two cornerposts.
 14. A freight container as claimed in claim 12, wherein saidlocking members include claw-shaped cams and matching cam keepers.